1. Field of the Invention
The present invention relates to a method of driving a plasma display panel which has display cells such as capacitive light emitting elements arranged in a matrix form.
2. Related Art
Japanese Patent No. 3424587 (Patent Document 1) discloses a known method of driving a plasma display panel. FIG. 1 shows driving waveforms disclosed in Patent Document 1. This figure shows the waveform at each of an address electrode and sustain discharge electrodes which include an X1 electrode, a Y1 electrode, an X2 electrode, and a Y2 electrode in an arbitrary sub-filed in one field for displaying an odd-numbered line. Each waveform includes a reset period, an addressing period, and a sustain discharge period. The following description will be given with reference to part of disclosed descriptions.
In the reset period, the address electrode is set to zero volt, followed by the application of a positive-polarity and a negative polarity pulse to the sustain discharge electrodes. Specifically, the X-electrodes are applied with a pulse having a voltage of −Vwx, while the Y-electrodes are applied with a pulse having a voltage of Vwy. In this event, the pulse applied to the Y-electrodes is a hang pulse which reaches the voltage Vwy while its voltage changing amount per unit time is changing. In this way, a first subtle discharge occurs between the X-electrodes and Y-electrodes. Since the use of the hang pulse causes each discharge cell to start a discharge at the time the applied voltages exceed a discharge start voltage Vf of each discharge cell, the resulting discharge is merely subtle, with a small amount of wall charges formed thereby. As a result, even if a reset discharge advances in a certain discharge cell, adjacent discharge cells are not affected thereby. Also, since the discharge is subtle, background light emission is also small.
Next, the X-electrodes are applied with a pulse having a voltage of Vex, while the Y-electrodes are applied with a pulse having a voltage of −Vey. In this event, the pulse applied to the Y-electrodes is a hang pulse which reaches the voltage −Vey while its voltage changing amount per unit time is changing. In this way, a second discharge occurs to erase the wall charge formed by the preceding discharge. Since a forced discharge occurs due to the application of a voltage Vex+Vey, an erasure discharge can be accomplished without fail.
Next, in the addressing period, a scanning pulse is sequentially applied to the Y-electrodes to perform an addressing discharge. Regarding the X-electrodes, a voltage Vx is applied to an X-electrode which is paired with a Y-electrode, which is applied with the scanning pulse, to constitute a displayed line, to perform the addressing discharge. On the other hand, a voltage of −Vux is applied to those X-electrodes which constitute non-displayed lines, with the intention to reduce a potential difference with the Y-electrodes to prevent the addressing discharge from occurring in the non-displayed lines.
Next, in the sustain discharge (sustain) period, a sustain pulse is applied alternately to the X-electrodes and Y-electrodes, causing sustain discharges to repeat in those cells in which the addressing discharge has been performed to display image data.